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Geomagnetic observatory data from

Huancayo, Peru, to investigate long-term trends in the equatorial electrojet region

Jürgen Matzka1, Claudia Stolle1,2, Tarique Adnan Siddiqui1, Lea Geibel1,3, Oscar Veliz4

1GFZ German Research Centre for Geosciences 2University Potsdam

3Inst. Of Geophysics. And Meteorology, Univ. of Cologne 4Instituto Geofísico del Perú

Quan%fying solar flux and geomagne%c main field influence on the equatorial thermosphere-‐ionosphere system for %mescales

complementary to satellite missions

A Project funded by the German Research Council through the Priority Programme “DynamicEarth”

•  originates in the Earth’s core, strong dipole plus mul%pole -‐> structured •  overall decrease over last centuries-‐> influence on ionospheric conduc%vity •  ver%cal at the magne%c poles, horizontal at the magne%c (dip) equator •  organises the external magnetospheric and ionospheric current systems

The geomagne?c field

The geomagne?c field: long term evolu?on of the South Atlan?c Anomaly

•  significant change over 70 years (%me scale of geomagne%c observatories) •  important for long term inves%ga%ons of the ionospheric current systems

The geomagne?c field: magne?c field strength (leE) and 10-‐year change (right)

•  10-‐year change can be significant (%me scale of satellite mission)

Geomagne?c observatories (INTERMAGNET consor?um)

•  INTERMAGNET observatories have high quality, only two are directly at the dip equator: Addis Ababa and Huancayo

!

Geomagne?c Field changes over 100 years: field strength and loca?on of the dip equator

Figure modified aRer Cnossen and Richmond, 2013

Geomagne%c Observatory Huancayo (code: HUA, ins%tute: IGP, Peru) •  Decreasing geomagne%c field strength at HUA and the American sector •  Dip equator posi%on stable at HUA and in the Asian and Pacific sector

Hourly mean values of H at HUA from World Data Centre

•  There are significant gaps in the 1960ies, 70ies, 80ies and 90ies.

1920 1930 1940 1950 1960 1970 1980 1990 2000 2010−5

0

5

10

D [d

egre

e]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

2.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs

black: HMV availalbe, red: current data gaps, green: newly discovered HMV

Data availability for HUA since 1922 and ‘newly found data’ (and F10.7)

•  Handwri^en tables fill in the longest gap and cover a solar cycle with low F10.7 max

Digital hourly mean values available from World Data Centre Gap in digital hourly mean values Handwri^en tables of hourly mean values: (World Data Centre Bolder and IGP, Peru)

What we see:

What we learn:

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16

Geomagne?c and solar parameters for Huancayo ?me series

What we see:

Horizontal field strength

What we learn:

Decrease by 19% -‐> conduc%vity

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16


What we see:

Inclina%on: 2.26° is 125 km, that gives

What we learn:

< 10% change in the magne%c signal of the EEJ

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16


What we see:

F10.7 -‐> conduc%vity

What we learn:

Low solar max cycles 20 and 24

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16


What we see:

Sunspot nr. further back than F10.7

What we learn:

Solar cycle 16 also very low

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16


1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16

Comparison with Addis ?me series

Addis Ababa geomagne%c observatory •  long term longitudinal comparison

Newly found microfilm from World Data Centre Boulder

•  arriving for digital scanning

Newly found microfilm from World Data Centre Boulder

•  one month: daily rows, columns by the hour, sums, quiet days mean varia%on

A first test: quiet day mean daily varia?on at HUA for previously missing data

1962J F M A M J J A S O N D

0 to 24 UT for January to December

HUA

mea

n da

ily v

aria

tion

for q

uiet

day

s of

H

1963

J F M A M J J A S O N D

1967


1968


1969


1970


1971


1972


1973


1974


1975


1976


1977


1978


1979


1980


For January to December: 0 to 24 UT

1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1963 1962

SoEware to retype handwri[en values

Hourly mean values of H at HUA

Hourly mean values of H at HUA 1961 to 1985

•  1961 to 1985: Almost completely, last data gaps are currently filled in

Hourly mean values of H at HUA in October 1963

•  Example for day2day-‐variability and Dst-‐effects(?)

Hourly mean values of H at HUA in October 1963

•  The night %me HUA H records follow nicely the Dst-‐index (Kyoto)


•  Difference in the World Data Centre (i.e. Winch, 1981) and our data set from May 1st, 1965


•  Difference in the World Data Centre (i.e. Winch, 1981) and our data set from August 1966

•  such differences can likely be resolved by -‐ analysis of data (seasonal means vs. F10.7, …) -‐ going back to historic opera%onal records

•  We have (almost) digi%sed the ‘newly found’ H-‐component

•  Next step: inves%gate homogeneity of the %me series •  Next step: inves%ga%ng long term trends due to

changing magne?c main field strength under defined (or corrected for) solar flux condi%ons

•  Further opportuni?es: -‐  Long term %dal signal -‐  Lunar %dal signal and Sudden Stratospheric Warming -‐  Day2day-‐variability -‐  … Data will be available at the World Data Centres for Geomagne?sm once also the ver%cal component Z and declina%on D are digi%sed and quality-‐checked.

Conclusion

Annual Mean Data Viewer: HUANCAYOAs recorded in 2014, mean calculated from all days

Dashed lines show annual means adjusted by jump values

1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010Years from 1922 to 2014

-175.0-150.0-125.0-100.0

-75 .0-50 .0-25 .0

.025.050.075.0

100.0125.0150.0175.0200.0225.0250.0275.0300.0325.0350.0375.0400.0425.0450.0475.0500.0

D, range 638min., mid-point 168min.

The ionospheric current systems

What we see:

Horizontal field strength

Inclina%on: 2.26° is 125 km, that gives F10.7 -‐> conduc%vity Sunspot nr. further back than F10.7

What we learn:

Decrease by 19% -‐> conduc%vity

< 10% change in the magne%c signal of the EEJ Low solar max cycles 20 and 24

Solar cycle 16 also very low

1920 1930 1940 1950 1960 1970 1980 1990 2000 20102.4

2.6

2.8

3x 104

H [n

T]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

1

2

3

I [de

gree

]

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

F10.

7

1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

100

200

300

suns

potn

umbe

rs


b)

c)

d)

a)

20 24

20 24

!

16


1

2 3

April 01 to 20, 1976

200300400500600

HM

V [n

T]

-300-200-1000

Dst

[nT]

Observatory: HUA Componenent: H Base: 27.000 nT Year: 1976 Month: April 13h - 14h 14h - 15h 15h - 16h17 (quiet) 482 536 57018 quiet 457 504

typical table ofHuancayo hourlymeanvalues (HMVs):handwritten,microfilmed,scanned image

masks displaying relevantparts of scanned image

mask for manual typing of HMVs

display of HMVs and Dst-index

data

bas

is

con

cept

of m

anua

l dig

itiza

tion

prog

ram

Title

Can check internal consitncy Of typing process

Documents

Geomagnetic observatory data from Huancayo, Peru, to ... › isea14 › sites › bdu.edu.et.isea14 › ...Geomagnetic observatory data from Huancayo, Peru, to investigate long-term